A is bollcks because as the previous poster states your at constant IAS and S &L so you would expect to increase the power input but CL would remain the same but the Cd would increase.
B is bollocks because if it wasn't you would be on the dirty side of the drag curve. I might happen but I doudt it.
C. The joker card of the oppersite to what actually happens.
D. The most plausable
These questions you will always get one like C which you can discount as being simply wrong then 3 others which have there merits. Then pick the one that is most plausable.